kube-scheduler在集群中的作用
    kube-scheduler是以插件形式存在的组件，正因为以插件形式存在，所以其具有可扩展可定制的特性。kube-scheduler相当于整个集群的调度决策者，其通过预选和优选两个过程决定容器的最佳调度位置。
    kube-scheduler源码中的关键性调用链
    9、kube-scheduler组件安装 - 图1
    kube-scheduler部署在hdss7-21,22上：
    创建启动脚本：vi /opt/kubernetes/server/bin/kube-scheduler.sh
    输入：
    #!/bin/sh
    ./kube-scheduler \
    —leader-elect \
    —log-dir /data/logs/kubernetes/kube-scheduler \
    —master http://127.0.0.1:8080 \
    —v 2

    执行权限：
    chmod +x /opt/kubernetes/server/bin/kube-scheduler.sh

    创建日志存储目录：
    mkdir -p /data/logs/kubernetes/kube-scheduler

    编辑supervisord脚本：
    vi /etc/supervisord.d/kube-scheduler.ini

    输入：
    [program:kube-scheduler-7-21]
    command=/opt/kubernetes/server/bin/kube-scheduler.sh ; the program (relative uses PATH, can take args)
    numprocs=1 ; number of processes copies to start (def 1)
    directory=/opt/kubernetes/server/bin ; directory to cwd to before exec (def no cwd)
    autostart=true ; start at supervisord start (default: true)
    autorestart=true ; retstart at unexpected quit (default: true)
    startsecs=30 ; number of secs prog must stay running (def. 1)
    startretries=3 ; max # of serial start failures (default 3)
    exitcodes=0,2 ; ‘expected’ exit codes for process (default 0,2)
    stopsignal=QUIT ; signal used to kill process (default TERM)
    stopwaitsecs=10 ; max num secs to wait b4 SIGKILL (default 10)
    user=root ; setuid to this UNIX account to run the program
    redirect_stderr=true ; redirect proc stderr to stdout (default false)
    stdout_logfile=/data/logs/kubernetes/kube-scheduler/scheduler.stdout.log ; stderr log path, NONE for none; default AUTO
    stdout_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
    stdout_logfile_backups=4 ; # of stdout logfile backups (default 10)
    stdout_capture_maxbytes=1MB ; number of bytes in ‘capturemode’ (default 0)
    stdout_events_enabled=false ; emit events on stdout writes (default false)

    更新supervisord：
    supervisorctl update

    supervisorctl status
    输出：
    etcd-server-7-22 RUNNING pid 1097, uptime 0:36:53
    kube-apiserver-7-22 RUNNING pid 1096, uptime 0:36:53
    kube-controller-manager-7-22 RUNNING pid 2170, uptime 0:14:13
    kube-scheduler-7-22 RUNNING pid 2320, uptime 0:00:42

    查看日志：
    tail -fn 200 /data/logs/kubernetes/kube-scheduler/scheduler.stdout.log

    短链接：
    ln -s /opt/kubernetes/server/bin/kubectl /usr/bin/kubectl

    检查一下状态：
    kubectl get cs

    输出：
    NAME STATUS MESSAGE ERROR
    controller-manager Healthy ok
    scheduler Healthy ok
    etcd-1 Healthy {“health”: “true”}
    etcd-0 Healthy {“health”: “true”}
    etcd-2 Healthy {“health”: “true”}